How do I fix a thermometer if the mercury has separated?
June 27, 2008 9:46 AM Subscribe
How do I fix a thermometer when the mercury has separated?
posted by odinsdream to science & nature (14 answers total)
I purchased a freezer thermometer. After getting it home the mercury (or whatever liquid they use in them now) had separated near the top of the scale, so there are bands of air between bands of red.
I tried heating it up, but this just compresses the band separation, then it returns to normal.
Instructions online say the fix is to get it cold enough that all of the liquid is pulled into the bulb. This thermometer goes to at least -35F on the readable scale, and a little past that before it reaches the bulb, probably -50F from the looks of it.
How can I fix it? Alternatively - do you work with liquid nitrogen and would you like to fix my thermometer?